The inkjet printing device of the related art that prints a desired image onto paper serving as the print media (object for printing) utilizes an ink cartridge for an inkjet recording device (hereafter, simply “ink cartridge”) that supplies ink into the ink head. This ink cartridge is a structure housed in a box-shaped outer package, and includes an ink supply section that extracts ink from an ink container storing ink.
The ink cartridge is preferably easy to attach and detach from the inkjet printing device, durable against vibrations during shipping as well as the dropping that occurs during shipping and the handling process, and also capable of low-cost manufacture. To meet these needs, the applicants propose an ink cartridge such as described in the following Patent Literature 1.
As schematically shown in FIG. 9, the ink cartridge 200 of the related art is a cuboid-shaped body detachable horizontally (direction for attaching/detaching) relative to the printing device, and containing an outer package 240 that is a long thin outer box, an engagement surface 220 that engages with the cartridge installation mechanism of the printing device formed at one end of the opening of the outer package 240, an ink supply section 230 that is mounted at the engagement surface 220 as the dispensing opening for ink, and an ink container 210 connecting to the ink supply section 230 and housed within the outer package 240. In FIG. 9, the ink container 210 is shown as a cuboid shape but in the drawing is merely an example that swells when filled with a specified quantity of ink.
In the step of manufacturing an ink cartridge with the above-described structure, the following procedure is performed particularly when filling a specified amount of ink into the ink container. First of all, as shown in FIG. 10, two sheets of cuboid shaped sheet material made of synthetic resin which is the material of the ink container 210 are stacked overlapping each other, and a connecting tube 250 having openings at both ends is installed in the center on that short side. The four sides of the sheet body are thermally fused while in that state, and a bag body connecting the inside and outside by way of that connecting tube 250 is configured. Oblique lines in FIG. 10 show the regions adhering due to thermal fusing. Next, the opening in the ink container 210 made by the connecting tube 250 is gripped in an erect state by a suitable unit, and ink injected internally into the internal part of the bag body from the connecting tube 250 to fill it by using an appropriate ink fill device. There is no particular need to apply pressure at this time. The opening of the connecting tube 250 is an appropriate width so that if ink is supplied, the ink is injected into the ink container 210 by the force of gravity and fills it. The supply of ink stops at the point where a specified amount of ink has been filled. An ink supply section 260 mounted a normally close on-off valve is then inserted into the connecting tube and is fixed so as to seal the ink in a liquid-tight state in the ink container 210. The ink container 210 filled with the specified amount of ink and capable of supplying ink to an outside section by way of the ink supply section 260 can therefore be configured in this way.
The synthetic resin sheet material that forms the ink container 210 is not necessarily always limited to two sheets and may be configured from more than that number of sheets but even in such cases, the effect is the same as the above-described two sheets of material in the point that the ink container 210 has the structure that the connecting tube 250 penetrates through a portion of the bag body of synthetic resin sheet material in a liquid-tight state.    Patent Literature 1: Japanese Unexamined Patent Application Publication No. 2010-82994